docs: def _filter_dicts(self):
          '''Filters out all the report_dicts that do not pass the cutoffs. If any ref sequence
             loses all of its report_dicts, then it is completely removed.'''
          keys_to_remove = set()
  
          for ref_name in self.report:
              for ctg_name in self.report[ref_name]:
                  self.report[ref_name][ctg_name] = self._filter_list_of_dicts(self.report[ref_name][ctg_name])
                  if len(self.report[ref_name][ctg_name]) == 0:
                      keys_to_remove.add((ref_name, ctg_name))
  
          refs_to_remove = set()
  
          for ref_name, ctg_name in keys_to_remove:
              del self.report[ref_name][ctg_name]
              if len(self.report[ref_name]) == 0:
                  refs_to_remove.add(ref_name)
  
          for ref_name in refs_to_remove:
              del self.report[ref_name]